Coloring leather.



UNITED STATES PATENT rrrc.

SAMUEL K. FELTON, JR, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO WILLIAM M. NORRIS, OF PRINCETON, NEW JERSEY.

COLORING LEATHER.

SPECIFICATION forming part of Letters Patent No. 645,291, dated March 13, 1900.

Application filed December 23, 1899. Serial No. 741, l33. (No specimens.)

To all whom it may concern..-

Be it known that I, SAMUEL K. FELTON, .Ir'. a citizen of the United States, and a resident of Philadelphia,Pennsylvania, have invented certain Improvements in Coloring Leather,of which the following is a specification.

My invention consists of a certain improvement in the method of coloring leather which has been proposed and which consists, mainly, in the treatment of the leather (after the same has been tanned and washed) with a solution of permanganate of potash, this treatment preceding the coloring or dyeing of the leather and being intended to produce more even shades of color than usual. I find,however, that by subjecting the leather to a staining or coloring treatment and to a fat-liquoring treatment before subjecting it to the permanganate treatment I am enabled to produce better results in the direction of uniformity and permanence of color than when the permanganate treatment immediately follows the tanning and washing process.

In carrying out my invention the skins after being tanned and. thoroughly washed to remove therefrom any trace of the tanning liquor are struck out and then shaved on the flesh side, so as to reduce the skin to as nearly uniform thickness as possible. By the term struck out as here used is meant the spreading or stretching of the skin to its full size and the expressing of the surplus wash liquor therefrom, this operation being performed either by one of the machines designed forthe purpose or by laying the skin upon a table or other suitable support and efiecting the desired result by an implement operated by hand. A number of the skins are then subjected to the action of a staining or coloring solution, and when the skins are to be subsequently colored black I prefer to use as the preliminary staining agent a logwood solution containing a small amount of anilin color--say about four ounces of blue and three ounces of vi0letto twenty-five gallons of logwood solution having a strength of one pound of logwood to the gallon, this amount being sufficient for the treatment of about five hundred pounds of skins. Any of the anilin blues or violets used in leather manufacture maybe employed, methyl violet being preferred. The skins and staining solution are preferably placed in a drum having inwardly-projecting pins or other means of causing agitation of the skins as the drum is turned, so as to insure the effective action of the staining solution on all parts of the skins. After being treated with the staining solution until they are thoroughly saturated therewith the skins are then subjected to the treatment known in the trade as fat-liquoring, the compound which I prefer to employ for this purpose being an emulsion of soft soap and neats-foot oil in the proportion of about thirty pounds of soap to three pints of oil, another pin-drum or equivalentforrn of apparatus being employed for insuring the thorough impregnation or saturation of the skins with the fat liquor. The skins are then smoothed out with a slicker and after being folded, grain side out,.each skin is dipped in a bath consisting of a solution of permanganate of potash, which I prepare, by preference, in the following manner: I dissolve ten pounds of permanganate in thirty gallons of water to form a stock solution,and of this stock solution I take one gallon to twelve gallons of water to form a bath capable of treating one hundred pounds of skins. In preparing the bath in the first instance the percentage of permanganate solution may be increased, say, to about three gallons; but after treating the first batch of skins an addition of one gallon of the solution for each subsequent batch of one hundred pounds of skins will be sufficient to maintain the bath at proper strength. After the skin has been washed to remove the free permanganate A therefrom the final coloring of the skin may have described a specific staining solution with which the skins are treated after the tanning process, this is intended for use only when a black color is desired. Hence I do not wish to be limited to the use of this particular solution, as any coloring solution may be used which accords with the final color desired and which will not injuriously affect or interfere with the subsequent treatment of the skin With the fat liquor. For instance, if a light or dark tan color is desired the preliminary coloring agent may be a solution of tanbark, gambier, or the like, the final coloring agent after the permanganate treatment being a solution of anilin color of the desired shade.

I find that by subjecting the skins to the treatment described preparatory to the permanganate treatment I am enabled to attain all of the advantages of the original process and at the same time produce more uniform and permanent coloring of the skins than when the process is carried out strictly in the manner set forth in the specification of said patent.

My invention is also applicable to skins tanned by the use of alum, bark, or other tanning agent, as Well as to chrome-tanned skins.

Having thus described my invention, I claim and desire to secure by Letters Patent The within-described process of coloring tanned leather which consists in subjecting said leather first to the action of a staining or coloring solution, then to a fat liquor, then to asolution of permanganate of pot-ash, and then to the final coloring agent or agents, substantially as specified.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

SAMUEL K. FELTON, JR.

Witnesses:

MURRAY G. BoYER, H. HAYES AIKENS. 

